add wrapper class around `apt_pkg.Hashes`

The interface changed in incompatible ways between Debian 10 (buster)
and Debian bullseye.

daklib/dakapt.py

+# -*- coding: utf-8 -*-
+
+"""
+interfaces around python-apt
+
+@copyright: 2020 😸 <😸@43-1.org>
+@license: GNU General Public License version 2 or later
+"""
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import apt_pkg
+
+"""
+wrapper around `apt_pkg.Hashes`
+"""
+class DakHashes(object):
+    def __init__(self, *args, **kwargs):
+        self._apt_hashes = apt_pkg.Hashes(*args, **kwargs)
+
+    # python-apt in Debian 10 (buster) uses
+    #   `apt_pkg.Hashes(...).md5`
+    # but in Debian bullseye it switched to
+    #   `apt_pkg.Hashes(...).find('md5sum').hashvalue`
+    def _hashvalue(self, attr, name):
+        if hasattr(self._apt_hashes, attr):
+            return getattr(self._apt_hashes, attr)
+        else:
+            return self._apt_hashes.hashes.find(name).hashvalue
+
+    @property
+    def md5(self):
+        return self._hashvalue('md5', 'md5sum')
+
+    @property
+    def sha1(self):
+        return self._hashvalue('sha1', 'sha1')
+
+    @property
+    def sha256(self):
+        return self._hashvalue('sha256', 'sha256')

daklib/import_repository.py

@@ -16,6 +16,7 @@
 
 import daklib.compress
 import daklib.config
+import daklib.dakapt
 import daklib.dbconn
 import daklib.gpg
 import daklib.upload
@@ -79,7 +80,7 @@ class File(object):
         return self._tmp
 
     def hashes(self):
-        return apt_pkg.Hashes(self.fh())
+        return daklib.dakapt.DakHashes(self.fh())
 
 
 def obtain_file(base, path):

daklib/upload.py

@@ -31,6 +31,7 @@ import six
 from daklib.aptversion import AptVersion
 from daklib.gpg import SignedFile
 from daklib.regexes import *
+import daklib.dakapt
 import daklib.packagelist
 
 
@@ -156,7 +157,7 @@ class HashedFile(object):
         path = os.path.join(directory, filename)
         with open(path, 'r') as fh:
             size = os.fstat(fh.fileno()).st_size
-            hashes = apt_pkg.Hashes(fh)
+            hashes = daklib.dakapt.DakHashes(fh)
         return cls(filename, size, hashes.md5, hashes.sha1, hashes.sha256, section, priority)
 
     def check(self, directory):
@@ -181,7 +182,7 @@ class HashedFile(object):
     def check_fh(self, fh):
         size = os.fstat(fh.fileno()).st_size
         fh.seek(0)
-        hashes = apt_pkg.Hashes(fh)
+        hashes = daklib.dakapt.DakHashes(fh)
 
         if size != self.size:
             raise InvalidHashException(self.filename, 'size', self.size, size)

tests/test_daklib_dakapt.py

+#! /usr/bin/python
+# -*- coding: utf-8 -*-
+#
+# © 2020, 😸 <😸@43-1.org>
+#
+# License: GPL-2+
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+
+from base_test import DakTestCase
+
+import daklib.dakapt
+
+class TestDakHashes(DakTestCase):
+    def testDakHashes(self):
+        hashes = daklib.dakapt.DakHashes("/dev/null")
+        self.assertEqual(hashes.md5, "d41d8cd98f00b204e9800998ecf8427e")
+        self.assertEqual(hashes.sha1, "da39a3ee5e6b4b0d3255bfef95601890afd80709")
+        self.assertEqual(hashes.sha256, "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")